function gogo(uImgs){
    let data1 = window.innerHeight||document.documentElement.clientHeight    // 可见视口高度
    let data2 = document.body.scrollTop||document.documentElement.scrollTop  //已经滚动的高度
    console.log(data1);
    let sum = data1+data2
    
    uImgs.forEach((item,i)=>{
        if(item.offsetTop<sum){
            item.src = item.getAttribute('src_real')
        }
    })
}